Osaka

Osaka Castle is one of Japan's most famous structures. It covers nearly 60,000 square meters in the center of the city, inviting the public to roam its gardens, its five stories, and its encompassing moat. Osaka castle also serves as the centerpiece of Japan's many national festivals, as vendors and taiko drummers scatter across the castle grounds.
More info: http://www.jnto.go.jp/eng/arrange/
attractions/facilities/castles/83dn3a000000ed4g.html